Re: [PATCH 0/4] I/O Error Handling for ReiserFS v3

[Jeff Mahoney <jeffm@novell.com>]

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Hans Reiser wrote:
| Alex Zarochentsev wrote:
|
|> On Tue, Oct 05, 2004 at 08:44:22AM -0700, Hans Reiser wrote:
|>
|>
|>> These have received design approval from zam (and thus me), but zam,
|>> did they receive stress testing by Elena under your guidance?
|>>
|>
|>
|> No. We have a long queue of test tasks.  There are fsck.reiser4 testing,
|> reiser4/dmapper crashes and the benchmarks in the queue.
|>
| Well, we cannot let our process be a barrier to good patches getting in,
| so let me ask, Jeff, did you test each of these conditions you
| improved?  How?  Did anyone else test them?

The "testing" version of the code had a another conditional added to
each of the !buffer_update tests that allowed me to trigger an I/O error
handling at each error point. The I/O error path is obviously more
difficult to test in real-world conditions as I/O errors could be caused
by any number of failures.

The testing was done using fsx-linux, the LTP fsstress program, and
stress.sh, sometimes all at once.

This code has also been active in the SUSE Linux Enterprise Server 9
kernel for some time and has seen real-world testing to show that the
normal path is still working as expected.

The end result for the i/o error path is that the write operations still
happen, but the commit block is never written. This means that the end
result is essentially the same as a power outage at the point of
failure. The filesystem is then read-only until the user decides to
umount and correct the problem that caused the I/O error in the first place.

- -Jeff

- --
Jeff Mahoney
SuSE Labs
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